Image reading apparatus provided with image sensor contained in slidable carriage

ABSTRACT

An image reading apparatus includes: a contact glass setting a manuscript thereon; an image sensor extending in a first direction and having a reading surface which faces the contact glass for reading an image from the manuscript on the contact glass; a rail member extending inside the apparatus main body in a second direction perpendicular to the first direction; a carriage having a sensor container to contain the image sensor, a taper end portion formed in an end portion in the first direction to become smaller in height toward the end side, and an opening formed in the bottom of the sensor container on the taper end portion side; a biased portion adjacent to the reading surface of the image sensor in the second direction; and a biasing member biasing the image sensor toward the contact glass via the biased portion.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent ApplicationNo. 2011-219219, filed on Oct. 3, 2011, the disclosure of which isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image reading apparatus which isconfigured to read an image from a manuscript on a contact glass by animage sensor contained in a carriage.

2. Description of the Related Art

Conventionally, as image reading apparatuses, so-called flatbed typeimage reading apparatuses have been known. Such an image readingapparatus has a contact glass at the upper surface of its main body forsetting a manuscript. The image reading apparatus is configured to readan image of the manuscript set on the contact glass by an image sensorprovided inside the main body. Then, the image sensor is installed on acarriage which is installed to be slidable on a rail provided inside themin body. The image sensor is configured to slide along the railtogether with the carriage when reading the image of the manuscript.

As a configuration of such image reading apparatus, it is known that theimage sensor has a longitudinal dimension in a main scanning directionand is placed on the carriage which is slidable along a guide shaft.Then, the image reading apparatus is configured to read an image of themanuscript set on the contact glass while sliding the image sensor,which is installed on the carriage, along the guide shaft.

In the abovementioned image reading apparatus, the carriage has abearing on its lower surface in the central portion in the longitudinaldirection. The bearing strides over the guide shaft from above to fitthe guide shaft thereinto. By letting the bearing fit the guide shaftthereinto from above, the carriage is installed to the guide shaft to beslidable along the guide shaft.

Here, the bearing is formed on the lower surface of the carriage in thecentral portion in the longitudinal direction. Therefore, the carriageis supported by one point in the longitudinal direction of the carriage,namely the central portion at which the bearing is formed. Hence, thecarriage is installed to the guide shaft swingably about the centralportion in the longitudinal direction.

Then, the carriage is formed to have an open top box-like shape in whichan upper surface on the contact glass side is open. The lower surface ofthe carriage is formed to have a uniform flat surface extending almoststraight. Therefore, if the carriage swings about the central portion inthe longitudinal direction, then one end portion of the carriage in thelongitudinal direction moves up toward the contact glass, while theother end portion moves downward below the guide shaft.

When the carriage is installed to the guide shaft in the above manner,inevitably, the carriage swings with the guide shaft and the bearingbeing a center. Therefore, the abovementioned image reading apparatusneeds to secure a space occupied by the carriage when the carriageswings, which becomes an obstacle to facilitating miniaturization of theimage reading apparatus.

Further, in the image reading apparatus, the distance between themanuscript on the contact glass and the reading surface of the imagesensor exerts an influence on the reading quality of the image readingapparatus. Therefore, even when the carriage has swung with the centralportion in the longitudinal direction being a center, it is stillnecessary to maintain the reading surface of the image sensor installedto the carriage parallel to the contact glass.

SUMMARY OF THE INVENTION

The present invention relates to an image reading apparatus which isconfigured to read an image front a manuscript on a contact glass by animage sensor contained in a carriage, and provides the image readingapparatus capable of maintaining the quality of reading images whilefacilitating miniaturization of the apparatus.

An image reading apparatus according to an aspect of the presentinvention has a main body, a contact glass, an image sensor extending ina first direction, a carriage, and a rail member supporting the carriageslidably in a second direction, and can read an image of a manuscriptset on the contact glass by sliding the image sensor contained in asensor container of the carriage, together with the carriage, along therail member. Here, the carriage is supported to be swingable about therail member at a central portion thereof in the first direction, and hasa taper end portion and an opening in an end portion thereof in thefirst direction. Since the taper end portion is formed to be smaller inheight toward the end side, when the carriage has swung about the railmember of the central portion in the first direction, it is possible toreduce the space occupied by the carriage in a swung state. Further,since the opening is formed on the taper end portion side, when thecarriage has swung, an end portion of the image sensor can projectdownward below the bottom surface of the carriage. Therefore, the imagereading apparatus can facilitate miniaturization of the apparatus byincluding the taper end portion and the opening in the end portion inthe first direction. Further, in the image reading apparatus, the imagesensor is biased toward the contact glass by a biasing member via abiased portion adjacent to a reading surface of the image sensor in thesecond direction, on the side of the taper end portion. Therefore, inthe image reading apparatus, since the biasing member is not positionedbetween the image sensor and the sensor container, it is also possibleto facilitate miniaturization of the apparatus. Further, in the imagereading apparatus, since the carriage has the opening on the side of thetaper end portion and the image sensor is biased by the biased portionand biasing member, even when the carriage has swung, it is stillpossible to keep a distance between the reading surface of the imagesensor and the contact glass constantly. Hence, it is possible for theimage reading apparatus to maintain the reading quality.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective external view of a multifunction apparatusaccording to an embodiment of the present invention.

FIG. 2 is a plan view showing an inner structure of a scanner unit ofthe multifunction apparatus.

FIG. 3 is a plan view of an image sensor installed on a carriage of themultifunction apparatus.

FIG. 4 is a perspective external view showing structures of the imagesensor and the carriage.

FIG. 5 is a cross-sectional view of a first holder member installed onthe carriage.

FIG. 6 is a plan view of the carriage.

FIG. 7 is a side view of the carriage.

FIG. 8 is a side view of the image sensor and the carriage when thecarriage is in a horizontal state.

FIG. 9 is a side view of the image sensor and the carriage when thecarriage is in a first inclined state.

FIG. 10 is a side view of the image sensor and the carriage when thecarriage is in a second inclined state.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Hereinbelow, referring to the accompanying drawings, explanations willbe made in detail with respect to an embodiment incorporating an imagereading apparatus in accordance with the present invention into amultifunction apparatus 1 having a scanner unit 10.

First, referring to FIGS. 1 and 2, a schematic configuration of themultifunction apparatus 1 in accordance with the embodiment will beexplained. Further, in the following explanations, with themultifunction apparatus 1 placed in a usable state as a reference, theup-down directions are defined as shown in FIG. 1. The lower right sidein FIG. 1 is defined as the front side, and the upper left side in FIG.1 is defined as the rear side. Further, with the multifunction apparatus1 viewed from the front side as a left-right reference, the lower leftside in FIG. 1 is defined as the left side, and the upper right side isdefined as the right side.

As shown in FIG. 1, the multifunction apparatus 1 has a main body 2 anda top cover 3. The main body 2 has a manuscript table 11 on an uppersurface of thereof. The manuscript table 11 has a contact glass 16. Thecontact glass 16 is a so-called “platen glass”. The contact glass 16 isformed to have a rectangular shape slightly larger than maximum size ofthe manuscript which the multifunction apparatus 1 can read. Along sideof the contact glass 16 is positioned along the left-right direction ofthe main body 2. The contact glass 16 is used when the manuscript is seton the contact glass 16 and an image is read by moving an aftermentionedimage sensor 20 which constitutes a scanner unit 10.

Further, the main body 2 has the scanner unit 10 below the contact glass16, namely, in an upper part of inner space of the main body 2. Thescanner unit 10 has the image sensor 20, a carriage 30, a slide shaft25, a reading transport motor, a flat cable, and the like. The scannerunit 10 reads an image of the manuscript set on the contact glass 16.The configuration of the scanner unit 10 will be explained in detailhereinafter in reference to the relevant figures.

Then, the main body 2 contains a control section, a facsimile section,an image formation section and the like below the scanner unit 10. Thecontrol section has a CPU, ROM, RAM, and the like. The control sectionplays a central role of the control for the multifunction apparatus 1 torealize a scanner function, a photocopy function, printer function, anda facsimile function.

The facsimile section transmits the manuscript image read by the scannerunit 10 to the destination desired by a user via a network based on thecontrol by the control section. Further, the facsimile section canreceive facsimile data via the network. The control section controls theimage formation section to print the received facsimile data on a sheetof printing paper or the like in a paper feed cassette 7. That is, themultifunction apparatus 1 realizes the facsimile function by controllingthe scanner unit 10, the facsimile section, and the image formationsection.

The image formation section prints the inputted image data onto theprinting paper transported from the paper feed cassette 7 based on thecontrol by the control section. The multifunction apparatus 1 controlsthe image formation section to process the image data corresponding tothe image read by the scanner unit 10, thereby realizing the photocopyfunction. Further, the multifunction apparatus 1 controls the imageformation section to process the print data inputted via the network,thereby realizing the printer function.

Further, an operation panel 5 and a liquid crystal display 6 areprovided on the upper surface on the front side of the main body 2. Theoperation panel 5 is manipulated to input various instructions to themultifunction apparatus 1. The liquid crystal display 6 displays variouskinds of information about the multifunction apparatus 1 to inform theuser of the contents of the information.

Further, the paper feed cassette 7 is installed to the main body 2 to beinsertable and removable through the front surface of the main body 2.The paper feed cassette 7 accommodates sheets of the printing paper as arecording medium in a stacked state. The printing paper is used to printthe image formed by the image formation section.

Then, the top cover 3 is provided to be openable and closeable with therear-end edge of the upper surface of the main body 2 as the axis. Whenthe top cover 3 is closed, the top cover 3 covers the upper surface ofthe main body 2, i.e. the manuscript table 11 and the contact glass 16.Therefore, the top cover 3 can fix the manuscript, which is set on thecontact glass 16, at that position.

Further, the top cover 3 has an auto document feeder 4 (ADF). The autodocument feeder 4 is provided on the left side of the top cover 3. Theauto document feeder 4 feeds the manuscripts in a manuscript tray (notshown) one by one consecutively and, after transporting the manuscriptsalong a predetermined transport path, discharges the manuscripts to apaper discharge tray (not shown). The multifunction apparatus 1 can readthe image of the manuscript in a manner in which the scanner unit 10reads the image in the course of transporting the manuscript by the autodocument feeder 4.

Next, referring to FIG. 2, explanations will be made in detail withrespect to a configuration of the scanner unit 10 of the multifunctionapparatus 1. As described above, the scanner unit 10 has the imagesensor 20, the carriage 30, the slide shaft 25, the reading transportmotor, the flat cable, and the like. The scanner unit 10 is providedbelow the contact glass 16 in the upper part of the main body 2.Further, in this embodiment, the portion, in the main body 2, at whichthe scanner unit 10 is provided is parted by a scanner bottom surface 17from a portion in which the facsimile section, the image formationsection and the like are accommodated.

The image sensor 20 is configured by a so-called contact image sensor(GIS). The image sensor 20 reads the image of the manuscript positionedon the contact glass 16. The image sensor 20 has a reading surface 21including an imaging element and the like at its upper surfacepositioned on the side of the contact glass 16. The image sensor 20 hasa reading range with a length equivalent to the short side of themaximum manuscript size in the main scanning direction, i.e. thefront-rear direction with respect to the main body 2. Further, the imagesensor 20 is formed to have an approximately cuboid shape and to extendin the main scanning direction. The image sensor 20 is contained in anaftermentioned sensor container 31 of the carriage 30.

As shown in FIG. 2, the slide shaft 25 is a shaft member having acircular rod form. The slide shaft 25 is provided over or above thescanner bottom surface 17 to extend toward the left and right directionsof the main body 2. The slide shaft 25 supports the image sensor 20 tobe slidable in the left-right direction via the carriage 30. Then, basedon the driving control by the control section, the reading transportmotor can slide the image sensor 20 which is installed on the carriage30 along the slide shaft 25 via a driving force transmission mechanismsuch as a pulley belt mechanism and the like.

Then, in the multifunction apparatus 1, the image sensor 20 is usuallylocated in a so-called home position, i.e. a standby position S underthe left end portion of the contact glass 16. As shown in FIG. 2, theimage sensor 20 can slide along the lower surface of the contact glass16 from the standby position S up to the position at a distanceequivalent to the long side of the maximum manuscript size (to bereferred to as “terminal position T” hereinbelow).

The image sensor 20 reads an image from the manuscript set on thecontact glass 16 when the image sensor 20 is moved between the standbyposition S and the terminal position T along a secondary scanningdirection parallel to the left-right direction of the multifunctionapparatus 1. Therefore, as shown in FIG. 1, the scanner unit 10 has themaximum reading range R equivalent to the maximum-sized manuscript andcan read an image of any manuscript not larger than the maximummanuscript size.

Next, referring to FIGS. 3 to 7, explanations will be made in detailwith respect to a configuration of the carriage 30 accommodating theimage sensor 20 in the scanner unit 10 according to this embodiment. Asdescribed above, the carriage 30 supports the image sensor 20 from belowand supports the image sensor 20 to be slidable along the slide shaft 25in the secondary scanning direction.

As shown in FIGS. 3 to 7, the carriage 30 includes the sensor container31, a first taper end portion 32, a second taper end portion 33, a firstopening 34, a second opening 35, first spring attachment portions 36,second spring attachment portions 37, and a shaft supporting portion 38.The carriage 30 extends in the front-rear direction of the multifunctionapparatus 1. The sensor container 31 is formed to have a recess which isopen toward the contact glass 16, and configured as a groove extendingalong the front-rear direction of the multifunction apparatus 1. Thesensor container 31 contains the image sensor 20 so that the readingsurface 21 of the image sensor 20 faces upward, i.e. toward the contactglass 16. The sensor container 31 supports the image sensor 20 frombelow.

The first taper end portion 32 is one end portion of the carriage 30 onthe front side in the longitudinal direction of the carriage 30. Thefirst taper end portion 32 is formed such that the carriage 30 becomessmaller in height as getting closer to the one end portion from thecentral portion in the longitudinal direction. As shown in FIG. 7, thelower-end edge of the first taper end portion 32 is formed to beinclined upwardly as getting closer to the one end portion from thecentral portion in the longitudinal direction. Further, a reference lineL FIG. 7 shows the position of the lower-end edge of the central portionin the longitudinal direction of the carriage 30 in a state that thecarriage 30 is in a horizontal state.

The second taper end portion 33 is the other end portion of the carriage30 on the rear side in the longitudinal direction of the carriage 30.Similar to the first taper end portion 32, the second taper end portion33 is formed such that the carriage 30 becomes smaller in height asgetting closer to the other end portion from the central portion in thelongitudinal direction. As shown in FIG. 7, the lower-end edge of thesecond taper end portion 33 is formed to be inclined upwardly withrespect to the reference line L as getting closer to the other endportion.

As shown in FIGS. 4 and 6, on the side of the first taper end portion32, the first opening 34 is formed to penetrate the bottom of the sensorcontainer 31 in a vertical direction with respect to the bottom of thesensor container 31. The first opening 34 is opened to have a size fromthe shaft supporting portion 38 formed in the central portion to thefirst taper end portion 32, in the longitudinal direction of thecarriage 30. With respect to the left-right direction of the carriage30, the first opening 34 is opened to have the size wider than a widthdimension of the image sensor 20 contained in the sensor container 31.Note that, the width dimension of the image sensor 20 means a dimensionin the left-right direction of the image sensor 20 contained in thesensor container 31, i.e. the secondary scanning direction. As describedabove, the inside of the sensor container 31 is formed to be capable ofcontaining the image sensor 20. Therefore, as shown in FIGS. 8 to 10,the front end of the image sensor 20 contained in the sensor container31 can enter below the bottom of the carriage 30 via the first opening34.

As shown in FIGS. 4 and 6, on the side of the second taper end portion33, the second opening 35 is formed to penetrate the bottom of thesensor container 31 in a vertical direction with respect to the bottomof the sensor container 31. The second opening 35 is opened to have asize from the shaft supporting portion 38 formed in the central portionto the second taper end portion 33, in the longitudinal direction of thecarriage 30. With respect to the left-right direction of the carriage30, the second opening 35 is opened to have the size wider than thewidth dimension of the image sensor 20 contained in the sensor container31 in. Therefore, as shown in FIGS. 8 to 10, the rear end of the imagesensor 20 contained in the sensor container 31 can also enter below thebottom of the carriage 30 via the second opening 35.

The first spring attachment portions 36 are formed on the side of thefirst taper end portion 32 in the longitudinal direction of the carriage30. The first spring attachment portions 36 are configured to be capableof attachment of a first holder member 40 and springs 50. As shown inFIGS. 3 to 6, the first spring attachment portions 36 are adjacent tothe sensor container 31 and face each other in the secondary scanningdirection of the multifunction apparatus 1 so that the sensor container31 is sandwiched therebetween.

The second spring attachment portions 37 are formed on the side of thesecond taper end portion 33 in the longitudinal direction of thecarriage 30. The second spring attachment portions 37 are configured tobe capable of attachment of a second holder member 45 and other springs50. As shown in FIGS. 3 to 6, similar to the first spring attachmentportions 36, the second spring attachment portions 37 are adjacent tothe sensor container 31 and face each other in the secondary scanningdirection of the multifunction apparatus 1 so that the sensor container31 is sandwiched therebetween.

The shaft supporting portion 38 is formed on the lower surface of thecentral portion in the longitudinal direction of the carriage 30. Theshaft supporting portion 38 is installed to the slide shaft 25 fromabove so that the shaft supporting portion 38 strides over the slideshaft 25. The shaft supporting portion 38 supports the carriage 30 to beslidable along the slide shaft 25 in the secondary scanning direction.As shown in FIGS. 8 to 10, the shaft supporting portion 38 supports thecarriage 30 to be swingable about the slide shaft 25.

As shown in FIGS. 4 and 5, the first holder member 40 supports the imagesensor 20 contained in the sensor container 31 from below. The firstholder member 40 holds the springs 50 between the first holder member 40and the first spring attachment portions 36. The first holder member 40has a sensor support portion 41, biased portions 42, and locking hooks43.

As shown in FIGS. 4 and 5, similar to the sensor container 31, thesensor support portion 41 is formed to have a recess which is openupward. The sensor support portion 41 supports the lower surface of theimage sensor 20 contained in the sensor container 31. Further, under acondition that the first holder member 40 is attached to the sensorcontainer 31, the sensor support portion 41 traverses the first opening34 in the secondary scanning direction at the position of forming thefirst spring attachment portions 36.

The biased portions 42 are formed to extend horizontally in outwarddirections with respect to the sensor support portion 41 from the twoupper ends of the sensor support portion 41 formed to have the recesswhich is open upward. The biased portions 42 retain the end portions ofthe springs 50 attached to the first spring attachment portions 36respectively. As shown in FIG. 5, under a condition that the firstholder member 40 is attached to the carriage 30, the biased portions 42are positioned above the first spring attachment portions 36,respectively. The biased portions 42 are biased upward by the springs 50retained on the first spring attachment portions 36, respectively.

Further, the locking hooks 43 axe hooks extending downward from the endedges of the respective biased portions 42 positioned outside of thesensor support portion 41. The locking hooks 43 have claw portions atthe lower end portions to project toward outside, respectively. Then, byengagement with engagement holes 31B formed in the carriage 30, thelocking hooks 43 fulfill the function of retaining the first holdermember 40 to prevent the first holder member 40 from coming off thecarriage 30.

As shown in FIG. 5, the engagement holes 31B are formed by cutting awaythe lower portions of the side walls of the carriage 30 on the left andright at the first spring attachment portions 36, respectively. Under acondition that the first holder member 40 is attached to the carriage30, the claw portions of the locking hooks 43 enter into the engagementholes 31B. Therefore, if the first holder member 40 moves upward by thebiasing force of the springs 50, then the claw portions of the lockinghooks 43 come into contact with the upper ends of the engagement holes31B. By these contacts, the first holder member 40 is retained in placewithout coining off the carriage 30, and thereby it is possible toprevent loss of the first holder member 40.

As shown in FIG. 4, the second holder member 45 supports the imagesensor 20 contained in the sensor container 31 from below. The secondholder member 45 holds the other springs 50 between the second holdermember 45 and the second spring attachment portions 37. The secondholder member 45 has a sensor support portion 46, biased portions 47,and locking hooks 48. The configuration of the second holder member 45is the same as that of the first holder member 40, and the sensorsupport portion 46, the biased portions 47 and the locking hooks 48 alsofunctionally correspond to the sensor support portion 41, the biasedportions 42 and the locking hooks 43 of the first holder member 40,respectively. Accordingly, explanations will be omitted with respect tothe sensor support portion 46 and the like of the second holder member45.

The springs 50 are provided between the biased portions 42 of the firstholder member 40 and the first spring attachment portions 36, andbetween the biased portions 47 of the second holder member 45 and thesecond spring attachment portions 37, respectively. The upper ends ofthe springs 50 make contact with the lower surfaces of the biasedportions 42 and biased portions 47. The lower ends of the springs 50 areretained on the first spring attachment portions 36 and the secondsprinz attachment portions 37.

As shown in FIG. 5, the upper ends of the springs 50 are positionedbelow the contact glass 16 and above the lower surface of the imagesensor 20 contained in the sensor container 31. Further, the firstspring attachment portions 36 retaining the lower ends of the springs 50are positioned above the lower surface of the image sensor 20 in thesensor container 31. Therefore, between the biased portions 42 of thefirst holder member 40 and the first spring attachment portions 36, thesprings 50 can bias the image sensor 20 along with the first holdermember 40 upward to the contact glass 16. Further, the same positionalrelation also adapts to the other springs 50 between the biased portions47 of the second holder member 45 and the second spring attachmentportions 37. Therefore, the other springs 50 can bias the image sensor20 along with the second holder member 45 upward to the contact glass16.

Then, as shown in FIG. 4, spacer members 60 are installed on the frontend portion and the rear end portion of the image sensor 20,respectively, such that a part of each of the spacer members 60 ispositioned upon the reading surface 21 of the image sensor 20.Therefore, the spacer members 60 is interposed between the readingsurface 21 of the image sensor 20 and the lower surface of the contactglass 16. That is, according to the multifunction apparatus 1, since thespacer members 60 make contact with the lower surface of the contactglass 16, it is possible to keep an appropriate distance between thecontact glass 16 and the reading surface 21 of the image sensor 20.Thereby, it is possible for the image sensor 20 to maintain the readingquality.

Next, referring to FIGS. 8 to 10, explanations will be made in detailwith respect to the states of the image sensor 20 and the carriage 30 ina case that the carriage is swung about the slide shaft 25. First,referring to FIG. 8, explanations will be given for a case in which thecarriage 30 is in a horizontal state.

As shown in FIG. 8, in a case that the carriage 30 is in a horizontalstate, the image sensor 20 maintains its horizontal state in the sensorcontainer 31, and thus the reading surface 21 is in a state parallel tothe contact glass 16. At this time, a part of the front end portion ofthe image sensor 20 is positioned below the carriage 30 via the firstopening 34. A part of the rear end portion of the image sensor 20 ispositioned below the carriage 30 via the second opening 35. That is, inthe horizontal state, a part of each end portion of the image sensor 20projects downward below the carriage 30 through either the first opening34 or the second opening 35 of the carriage 30.

Next, referring to FIG. 9, explanations will be given in detail for acase in which the carriage 30 is in a first inclined state. The firstinclined state means a state in which the carriage 30 has swung aboutthe slide shaft 25 such that the first taper end portion 32 moves upwardand the second taper end portion 33 moves downward.

As shown in FIG. 9, if the carriage 30 swings about the slide shaft 25and comes into the first inclined state, then, the front end portion ofthe image sensor 20 projects further downward via the first opening 34of the first taper end portion 32. Therefore, more part of the front endportion of the image sensor 20 is positioned below the carriage 30 ascompared with the state shown in FIG. 8. On the other hand, in thiscase, the rear end portion of the image sensor 20 projects upwardthrough the second opening 35 of the second taper end portion 33 due tothe biasing force of the springs 50 via the second holder member 45.Therefore, as shown in FIG. 9, even when the carriage 30 is in the firstinclined state, the image sensor 20 can still keep the reading surface21 in the horizontal state.

Further, when the carriage 30 is in the first inclined state, the secondtaper end portion 33 of the carriage 30 has moved below as compared withthe horizontal state shown in FIG. 8. The second taper end portion 33 isformed such that the dimension of the carriage 30 in height becomessmaller as getting closer to the rear end side from the central portionin the longitudinal direction. The lower-end edge of the second taperend portion 33 is inclined upward toward the rear end side with respectto the reference line L. Therefore, as shown in FIG. 9, even when thecarriage 30 is in the first inclined state, the second taper end portion33 is still positioned above the reference line L. That is, according tothe multifunction apparatus 1, even in the first inclined state, thecarriage 30 does not occupy any space below the reference line L. As aresult, since the space below the reference line L in the multifunctionapparatus 1 can be used effectively, it is possible to facilitateapparatus miniaturization for the multifunction apparatus 1.

Next, referring to FIG. 10, explanations will be given in detail for acase in which the carriage 30 is in a second inclined state. Here, thesecond inclined state means a state in which the carriage 30 has swungabout the slide shaft 25 such that the first taper end portion 32 movesdownward and the second taper end portion 33 moves upward.

As shown in FIG. 10, if the carriage 30 swings about the slide shaft 25and comes into the second inclined state, then the rear end portion ofthe image sensor 20 projects further downward via the second opening 35of the second taper end portion 33. Therefore, more part of the rear endportion of the image sensor 20 is positioned below the carriage 30 ascompared with the state shown in FIG. 8. On the other hand, in thiscase, the front end portion of the image sensor 20 projects upwardthrough the first opening 34 of the first taper end portion 32 due tothe biasing force of the springs 50 via the first holder member 40.Therefore, as shown in FIG. 10, even when the carriage 30 is in thesecond inclined state, the image sensor 20 can still keep the readingsurface 21 in the horizontal state.

Further, when the carriage 30 is in the second inclined state, the firsttaper end portion 32 of the carriage 30 has moved below as compared withthe horizontal state shown in FIG. 8. The first taper end portion 32 isformed such that the dimension of the carriage 30 in height becomessmaller as getting closer to the front end side from the central portionin the longitudinal direction. The lower-end edge of the first taper endportion 32 is inclined upward toward the front end side with respect tothe reference line L. Therefore, as shown in FIG. 10, even when thecarriage 30 is in the second inclined state, the first taper end portion32 is still positioned above the reference line L. That is, according tothe multifunction apparatus 1, even in the second inclined state, thecarriage 30 does not occupy any space below the reference line L. As aresult, since the space below the reference line L in the multifunctionapparatus 1 can be used deffectively, it is possible to facilitateapparatus miniaturization for the multifunction apparatus 1.

As described above, in the multifunction apparatus 1 according to thepresent embodiment, the carriage 30 is formed with the first taper endportion 32 and the second taper end portion 33. Accordingly, as shown inFIGS. 8 to 10, even when the carriage 30 has swung about the slide shaft25, the carriage 30 does not occupy any space below the reference lineL. Therefore, according to the multifunction apparatus 1, it is possibleto effectively utilize the space below the reference line L and it ispossible to facilitate miniaturization of the multifunction apparatus 1.

In the multifunction apparatus 1, the first opening 34 is formed in thefirst taper end portion 32. The first holder member 40 and the springs50 are attached to the first taper end portion 32. Further, the secondopening 35 is firmed in the second taper end portion 33. The secondholder member 45 and the other springs 50 are attached to the secondtaper end portion 33. Therefore, according to the multifunctionapparatus 1, as shown in FIGS. 8 to 10, even if the carriage 30 swingsabout the slide shaft 25, it is still possible to keep the readingsurface 21 of the image sensor 20 horizontal with respect to the contactglass 16. Hence, it is possible for the multifunction apparatus 1 tomaintain the quality of reading images.

Further, in the multifunction apparatus 1, the biased portions 42 of thefirst holder member 40 and the biased portions 47 of the second holdermember 45 are adjacent to the reading surface 21 of the image sensor 20in the sensor container 31 in the left-right direction. Then, betweenthe biased portions 42 and the first spring attachment portions 36, andbetween the biased portions 47 and the second spring attachment portions37, the springs 50 bias the biased portions 42 and the biased portions47 upward, respectively. Therefore, as shown in FIGS. 3 to 5, in themultifunction apparatus 1 according to this embodiment, the springs 50are not positioned between the lower surface of the image sensor 20 andthe sensor container 31. As a result, it is possible for themultifunction apparatus 1 to reduce the vertical dimension of the imagesensor 20 and carriage 30. Hence, it is possible to facilitateminiaturization of the apparatus in the up-down direction.

Further, as shown in FIG. 3, when viewed from upside of the readingsurface 21 of the image sensor 20 in the sensor container 31, the biasedportions of the present invention are adjacent to the reading surface21. That is, as long as this condition is satisfied, the biased portionsmay be positioned at any position in the up-down direction with respectto the reading surface 21 of the image sensor 20. For example, as longas the above condition is satisfied, the biased portions may bepositioned either above the reading surface 21 or below the readingsurface 21. Further, the biased portions may also be at the same heightwith the reading surface 21.

Further, the biased portions 42 of the first holder member 40 and thebiased portions 47 of the second holder member 45 are adjacent to thereading surface 21 of the image sensor 20 in the sensor container 31 inthe left-right direction. The biased portions 42 of the first holdermember 40 and the biased portions 47 of the second holder member 45 arebiased upward by the springs 50. That is, according to the multifunctionapparatus 1, it is possible to balance the biasing three of the springs50 for the image sensor 20 in the left-right direction. Therefore, it ispossible to bias the reading surface 21 of the image sensor 20 towardthe contact glass 16 in an appropriate state, i.e., being kept in ahorizontal state.

Based on the embodiment, the present invention was described above.However, the present invention is not limited in any way to theembodiment described above, but can undergo various modifications andchanges without departing from the gist and scope of the presentinvention. For example, in the above embodiment, an example is shown bythe multifunction apparatus 1 having a scanner function, a photocopyfunction, a printer function, and a facsimile function. However, thepresent invention is not limited to this aspect. It is possible to applythe present invention to any scanner apparatuses or photocopy machineswhich have at least a scanner unit of the flatbed type.

Further, in the above embodiment, the biased portions of the holdermember are biased upward by the springs so as to bias the image sensorsupported by the holder member toward the contact glass. However, thepresent invention is not limited to this aspect. For example, in theupper portions of the side surfaces of the image sensor, biased portionsmay be formed to extend horizontally in outward directions from theimage sensor. In this case, by exerting the biasing force of the springson the biased portions formed integrally with the image sensor, theimage sensor may also be biased toward the contact glass.

That is, the biased portions of the present invention may be configuredto first receive the biasing force of a biasing member at positionsadjacent to the reading surface of the image sensor, and then exert thebiasing force to bias the image sensor toward the contact glass.Therefore, as described above, the biased portions of the presentinvention include the biased portions formed integrally with the imagesensor. Further, as in the embodiment described above, it is a matter ofcourse that the biased portions also include with the biased portionswhich is formed in other members different from the image sensor.

Then, in the above embodiment, the first taper end portion 32, the firstopening 34, the first holder member 40, and some of the springs 50 areprovided in one end portion of the carriage 30 in the longitudinaldirection. The second taper end portion 33, the second opening 35, thesecond holder member 45, and the other springs 50 are provided in theother end portion. However, the present invention is not limited to thisaspect. It may also be configured to provide a taper end, an opening,biased portions, and a biasing member in at least one end portion of thecarriage in the longitudinal direction, and such configuration isincluded in the invention according to claim 1 of the presentapplication.

Further, in the above embodiment, as shown in FIGS. 8 to 10, in each ofthe horizontal state, the first inclined state and the second inclinedstate, at least one end portion of the image sensor 20 enters under thecarriage 30 via either the first opening 34 or the second opening 35.However, the present invention is not limited to this aspect. Thepresent invention includes any configurations such that in any one ofthe horizontal state, the first inclined state and the second inclinedstate, an end portion of the image sensor enters under the carriage viaan opening. For example, the present invention includes theconfiguration that no end portion of the image sensor enters under thecarriage via the opening in the horizontal state, but an end portion ofthe image sensor enters under the carriage via the opening in the firstinclined state and/or in the second inclined state.

What is claimed is:
 1. An image reading apparatus configured to read animage of a manuscript, the apparatus comprising: a main body; a contactglass provided at an upper surface of the main body to set themanuscript thereon; an image sensor provided on a side opposite to asurface of the contact glass on which the manuscript is set, the imagesensor extending in a first direction and having a reading surface whichfaces the contact glass to read the image from the manuscript on thecontact glass; a rail member extending inside the main body in a seconddirection perpendicular to the first direction; a carriage which issupported by the rail member to be slidable along the second directionand contains the image sensor in a sensor container having a recess opento a contact glass side, the carriage being supported to be swingableabout the rail member at a central portion thereof in the firstdirection, and having an opening which is formed in the carriage on oneend side in the first direction and which penetrates a bottom surface ofthe sensor container to permit an end portion of the image sensor toproject downward below the bottom surface of the carriage; a biasedportion which is provided on the one end side in the first directionwith respect to the carriage, and which is adjacent, in the seconddirection, to the reading surface of the image sensor; and a biasingmember provided between the biased portion and the carriage to bias theimage sensor toward the contact glass via the biased portion.
 2. Theimage reading apparatus according to claim 1 further comprising a holdermember which is provided to be movable toward and away from the contactglass between the carriage and the contact glass and which traverses theopening along the second direction, wherein the holder member has: asupport recess which is formed to open toward the contact glass and totraverse the opening along the second direction and which contacts withthe lower surface of the image sensor to support the image sensor; andthe biased portion extending out toward outside of the support recessfrom an end edge, of the support recess, on the contact glass side. 3.The image reading apparatus according to claim 1, wherein the biasingmember is a spring.
 4. The image reading apparatus according to claim 1,wherein the rail member is a shaft.
 5. The image reading apparatusaccording to claim 1, further comprising a stopper which prevents thebiased portion from being separated from the carriage by more than apredetermined distance.
 6. An image reading apparatus configured to readan image of a manuscript, the apparatus comprising: a main body; acontact glass provided at an upper surface of the main body to set themanuscript thereon; an image sensor provided on a side opposite to asurface of the contact glass on which the manuscript is set, the imagesensor extending in a first direction and having a reading surface whichfaces the contact glass to read the image from the manuscript on thecontact glass; a rail member extending inside the main body in a seconddirection perpendicular to the first direction; a carriage which issupported by the rail member to be slidable along the second directionand contains the image sensor in a sensor container having a recess opento a contact glass side, the carriage being supported to be swingableabout the rail member at a central portion thereof in the firstdirection, and having: a first opening which is formed in the carriageon one end side in the first direction and which penetrates a bottomsurface of the sensor container and configured to permit one end portionof the image sensor to project downward below the bottom surface of thecarriage; and a second opening which is formed in the carriage on theother end side in the first direction and which penetrates the bottomsurface of the sensor container to permit the other end portion of theimage sensor to project downward below the bottom surface of thecarriage; a first biased portion which is provided on the one end sidein the first direction with respect to the carriage, and which isadjacent, in the second direction, to the reading surface of the imagesensor; a second biased portion which is provided on the other end sidein the first direction with respect to the carriage, and which isadjacent, in the second direction, to the reading surface of the imagesensor; a first biasing member provided between the first biased portionand the carriage to bias the image sensor toward the contact glass viathe first biased portion; and a second biasing member provided betweenthe second biased portion and the carriage to bias the image sensortoward the contact glass via the second biased portion.
 7. The imagereading apparatus according to claim 6, further comprising: a firstholder member which is provided to be movable toward and away from thecontact glass between the carriage and the contact glass and whichtraverses the first opening along the second direction; and a secondholder member which is provided to be movable toward and away from thecontact glass between the carriage and the contact glass and whichtraverses the second opening along the second direction, wherein thefirst holder member has: a first support recess which is formed to opentoward the contact glass and to traverse the first opening along thesecond direction and which contacts with the lower surface of the imagesensor to support the image sensor; and the first biased portionextending out toward outside of the first support recess from an endedge, of the first support recess, on the contact glass side, andwherein the second holder member has: a second support recess which isformed to open toward the contact glass and to traverse the secondopening along the second direction and which contacts with the lowersurface of the image sensor to support the image sensor; and the secondbiased portion extending out toward outside of the second support recessfrom an end edge, of the second support recess, on the contact glassside.
 8. The image reading apparatus according to claim 7, wherein thefirst biasing member and the second biasing member are springs.
 9. Theimage reading apparatus according to claim 7, wherein the rail member isa shaft.
 10. The image reading apparatus according to claim 7, furthercomprising a first stopper which prevents the first biased portion frombeing separated from the carriage by more than a predetermined distanceand a second stopper which prevents the second biased portion from beingseparated from the carriage by more than the predetermined distance.